Fifty Years of Research in ARDS. Is Acute Respiratory Distress Syndrome a Preventable Disease?

Friend or foe: the role of platelets in acute lung injury

Lung diseases, including acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), are associated with various etiological factors and are characterized by high mortality rates. Current treatment strategies primarily focus on lung-protective ventilation and careful fluid management. Despite over 50 years of basic and clinical research, effective treatment options remain limited, and the search for novel strategies continues. Traditionally, platelets have been viewed primarily as contributors to blood coagulation; however, recent research has revealed their significant role in inflammation and immune regulation. While the relationship between platelet count and ALI/ARDS has remained unclear, emerging studies highlight the "dual role" of platelets in these conditions. On one hand, platelets interact with neutrophils to form neutrophil extracellular traps (NETs), promoting immune thrombosis and exacerbating lung inflammation. On the other hand, platelets also play a protective role by modulating inflammation, promoting regulatory T cell (Treg) activity, and assisting in alveolar macrophage reprogramming. This dual functionality of platelets has important implications for the pathogenesis and resolution of ALI/ARDS. This review examines the multifaceted roles of platelets in ALI/ARDS, focusing on their immunomodulatory effects, the platelet-neutrophil interaction, and the critical involvement of platelet-Treg cell complexes in shaping the inflammatory environment in ALI.

Predictive Modeling of Acute Respiratory Distress Syndrome Using Machine Learning: Systematic Review and Meta-Analysis

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a critical condition commonly encountered in the intensive care unit (ICU), characterized by a high incidence and substantial mortality rate. Early detection and accurate prediction of ARDS can significantly improve patient outcomes. While machine learning (ML) models are increasingly being used for ARDS prediction, there is a lack of consensus on the most effective model or methodology. This study is the first to systematically evaluate the performance of ARDS prediction models based on multiple quantitative data sources. We compare the effectiveness of ML models via a meta-analysis, revealing factors affecting performance and suggesting strategies to enhance generalization and prediction accuracy.

OBJECTIVE

This study aims to evaluate the performance of existing ARDS prediction models through a systematic review and meta-analysis, using metrics such as area under the receiver operating characteristic curve, sensitivity, specificity, and other relevant indicators. The findings will provide evidence-based insights to support the development of more accurate and effective ARDS prediction tools.

METHODS

We performed a search across 6 electronic databases for studies developing ML predictive models for ARDS, with a cutoff date of December 29, 2024. The risk of bias in these models was evaluated using the Prediction model Risk of Bias Assessment Tool. Meta-analyses and investigations into heterogeneity were carried out using Meta-DiSc software (version 1.4), developed by the Ramón y Cajal Hospital's Clinical Biostatistics team in Madrid, Spain. Furthermore, sensitivity, subgroup, and meta-regression analyses were used to explore the sources of heterogeneity more comprehensively.

RESULTS

ML models achieved a pooled area under the receiver operating characteristic curve of 0.7407 for ARDS. The additional metrics were as follows: sensitivity was 0.67 (95% CI 0.66-0.67; P<.001; I²=97.1%), specificity was 0.68 (95% CI 0.67-0.68; P<.001; I²=98.5%), the diagnostic odds ratio was 6.26 (95% CI 4.93-7.94; P<.001; I²=95.3%), the positive likelihood ratio was 2.80 (95% CI 2.46-3.19; P<.001; I²=97.3%), and the negative likelihood ratio was 0.51 (95% CI 0.46-0.57; P<.001; I²=93.6%).

CONCLUSIONS

This study evaluates prediction models constructed using various ML algorithms, with results showing that ML demonstrates high performance in ARDS prediction. However, many of the existing models still have limitations. During model development, it is essential to focus on model quality, including reducing bias risk, designing appropriate sample sizes, conducting external validation, and ensuring model interpretability. Additionally, challenges such as physician trust and the need for prospective validation must also be addressed. Future research should standardize model development, optimize model performance, and explore how to better integrate predictive models into clinical practice to improve ARDS diagnosis and risk stratification.

TRIAL REGISTRATION

PROSPERO CRD42024529403; https://www.crd.york.ac.uk/PROSPERO/view/CRD42024529403.

Panax notoginseng saponins ameliorate LPS-induced acute lung injury by promoting STAT6-mediated M2-like macrophage polarization

BACKGROUND

Acute lung injury (ALI) is a severe inflammatory condition characterized by dysregulated immune responses and high mortality rates, with limited effective therapeutic options currently available. Panax notoginseng saponins (PNS), bioactive compounds derived from Panax notoginseng, have shown promise in mitigating lipopolysaccharide (LPS)-induced ALI. However, the molecular mechanisms underlying their therapeutic effects remain poorly understood. Given the critical role of M2-like macrophage polarization in resolving inflammation and promoting tissue repair, we investigated whether PNS exerts its protective effects in ALI by modulating this process. Furthermore, we explored the specific involvement of the signal transducer and activator of transcription 6 (STAT6) pathway in mediating these effects.

METHODS

Chemical profiling of PNS was performed using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), followed by quantitative analysis of its major bioactive components via high-performance liquid chromatography (HPLC). To evaluate the therapeutic efficacy of PNS and its principal constituents, we established an ALI mouse model through intratracheal administration of LPS. Comprehensive assessments included lung field shadowing, oxygen saturation levels, pulmonary function, and systematic histopathological examination. The regulatory effects of PNS on macrophage polarization were examined in THP-1 cells and bone marrow-derived macrophages (BMDMs), with cellular phenotypes analyzed by flow cytometry. To elucidate the mechanistic role of STAT6 in PNS-mediated protection, experiments were conducted using Stat6-deficient BMDMs and Stat6 knockout mice.

RESULTS

UPLC-Q-TOF-MS and HPLC identified and quantified the principal components of PNS: Notoginsenoside R1, Ginsenoside Rg1, Ginsenoside Re, and Ginsenoside Rb1. PNS treatment dose-dependently reduced inflammatory responses in LPS-induced ALI mice, as evidenced by decreased cytokine levels. Each of the four major PNS components independently alleviated ALI symptoms in mice. Pathway analysis revealed 56 potential ALI-related targets, with Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment suggesting that PNS exerts its protective effects by modulating inflammatory signaling pathways. In vitro studies demonstrated that PNS promoted STAT6 phosphorylation and nuclear translocation, enhancing M2-like macrophage polarization and interleukin-10 (IL-10) secretion in a STAT6-dependent manner. Genetic ablation of Stat6 partially reversed the protective effects of PNS on ALI, macrophage polarization, and IL-10 production, confirming the pivotal role of STAT6 in mediating PNS activity.

CONCLUSION

This study demonstrates that PNS alleviates LPS-induced ALI by promoting STAT6-dependent M2-like macrophage polarization, highlighting its potential as a therapeutic agent for ALI. These findings provide mechanistic insights into the anti-inflammatory actions of PNS and underscore the importance of STAT6 signaling in its protective effects.

Associated effects of lipopolysaccharide, oleic acid, and lung injury ventilator-induced in developing a model of moderate acute respiratory distress syndrome in New Zealand white rabbits

Acute respiratory distress syndrome (ARDS) is a critical pulmonary disorder with manifestations of pulmonary edema, inflammation, and impaired oxygenation. Establishing reliable animal ARDS models has been critical for investigating its mechanisms and for testing pharmacological interventions. The present study sought to induce a moderate ARDS model in New Zealand White rabbits with a model involving a mix of lipopolysaccharide (LPS), oleic acid (OA), and ventilation-induced lung injury (VILI). Four experimental groups were established: negative control (NC, n = 4), OA (OM, n = 6), LPS + OA (LOM, n = 6), and LPS + OA + VILI (LOV, n = 6). Throughout the modeling process, vital signs (MAP and HR), respiratory parameters (Cdyn), and hematological indices (WBC and P/F) were continuously monitored, and lung ultrasound was performed. After the experiment, bronchoalveolar lavage fluid (BALF) was collected to measure total protein content, and lung tissue samples were collected to determine the wet-to-dry (W/D) ratio. HE-stained lung tissue sections were prepared and scored according to the ATS guidelines for lung injury scoring. The LOV group showed the most severe lung injury, significantly decreasing MAP and Cdyn. Pathological and ultrasound scores were considerably higher in the LOV group compared to the OM and LOM groups (p < 0.05). The lung W/D ratio was significantly higher in the LOM (6.68 ± 0.56) and LOV (7.40 ± 0.56) groups compared to the NC group (5.20 ± 0.16) (p < 0.05). At T6, the PaO2/FiO2 ratio in the LOV group was ≤200 mmHg, significantly lower than that in the NC group (p < 0.05). Some rabbits in the OM and LOM groups also had PaO2/FiO2 ratios ≤200 mmHg, but the difference compared to the NC group was not statistically significant. In conclusion, this study established a novel moderate ARDS model in New Zealand White rabbits using LPS, OA, and VILI. The model demonstrates severe lung damage, pulmonary edema, and sustained hypoxemia, providing a basis for future research.

Triptolide alleviates acute lung injury by reducing mitochondrial dysfunction mediated ferroptosis through the STAT3/p53 pathway

Acute lung injury (ALI) represents a severe clinical condition marked by intense pulmonary inflammation and complex pathogenic mechanisms. Triptolide, a potent anti-inflammatory agent derived from the plant Tripterygium wilfordii Hook. f., remains to be fully elucidated for its therapeutic efficacy in ALI. This study aimed to investigate the potential of triptolide in mitigating ALI by modulating ferroptosis and preserving mitochondrial function. Utilizing an ALI model induced by lipopolysaccharide (LPS) both in mice and BEAS-2B cells, we evaluated the impact of triptolide on lung injury, inflammatory cytokines, oxidative stress, and mitochondrial function. RNA sequencing, network pharmacology, molecular docking, and a thermal stability assay for cellular proteins (CETSA) were utilized to identify triptolide targets and pathways. Triptolide significantly alleviated LPS-induced pulmonary pathological changes, downregulated inflammatory cytokines including IL-6, IL-1β, and TNF-α, and reduced reactive oxygen species (ROS) and malondialdehyde (MDA) levels while increasing glutathione (GSH) and superoxide dismutase (SOD) activity. RNA sequencing revealed that triptolide upregulated SLC7A11 and inhibited ferroptosis. Network pharmacology and molecular docking identified the STAT3/p53 pathway as a key mediator of triptolide's action. CETSA confirmed that triptolide binds to and enhances the thermal stability of STAT3 and p53 proteins. This study is the first to elucidate that triptolide mitigates ALI by targeting the STAT3/p53 pathway, preserving mitochondrial function, and inhibiting ferroptosis. Collectively, these results propose that triptolide may serve as an effective therapeutic option for the treatment of ALI.

Evaluating the Use of Inhaled Budesonide and Ipratropium Bromide Combination in Patients at High Risk of Acute Respiratory Distress Syndrome Development: A Randomized Controlled Trial

Objectives: There is a scarcity of pharmacological treatments that efficiently address lung injury in individuals experiencing acute respiratory distress syndrome (ARDS). Early inhaled corticosteroids and ipratropium may reduce pulmonary inflammation and injury of the lungs, minimizing the risk of ARDS. Method: This is a double-blinded randomized control trial conducted on patients at risk of ARDS. Patients were randomly allocated into two groups; the intervention group (63 patients) were administered aerosolized budesonide and ipratropium bromide, and the control group (56) were administered a placebo every eight hours for five days. Alteration in oxygen saturation divided by inspired oxygen (Fio2) (S/F) after five days was the primary outcome. Secondary outcomes included ARDS occurrence, mechanical ventilation (MV) requirement, hospital stay duration, and mortality rates. Results: Of the 604 screened, only 119 patients were included. The intervention group (63 patients) S/F ratio recovered versus the fall of the control group. Both groups had similar organ dysfunction and 28-day mortality. The intervention group had significantly (p < 0.001) fewer cases developing ARDS (9.5%) and MV (9.5%) than the control group (46.4% and 35.7%, respectively). Conclusions: The administration of inhaled budesonide and ipratropium bromide improved oxygenation, as assessed by the S/F ratio, and significantly reduced the rate of ARDS development and the requirement of MV versus the control group. Larger multi-center trials including diverse patient populations are needed to validate these results.

Holistic Patient-Centered Outcomes in Post-Acute Kidney Injury Care: Physical, Emotional, Cognitive, and Social Outcomes

Acute kidney injury can lead to severe short- and long-term consequences. The majority of acute kidney injury outcome studies have focused on mortality and kidney-related outcomes, with very few studies considering the importance of a holistic approach to post-acute kidney injury care. In this review, we focus on the physical, emotional, cognitive, and social outcomes following acute kidney injury that may affect patients' quality of life, aiming to highlight the importance of assessing and managing patients both during their hospitalization as well as posthospital discharge. We conclude with specific key recommendations to ensure that health care providers consider all aspects of care for patients with acute kidney injury, and we advocate for a concerted effort to develop post-acute kidney injury care strategies that embrace a holistic approach, ensuring comprehensive care for acute kidney injury survivors.

Strategies for preventing and reducing the impact of acute respiratory failure from pneumonia

INTRODUCTION

Pneumonia remains a leading cause of morbidity and mortality, particularly in critically ill patients with acute respiratory failure (ARF). This review discusses prevention strategies for pneumonia-induced ARF, categorized into primary, secondary, and tertiary prevention.

AREAS COVERED

A literature search was conducted through PubMed covering the years 2000-2024, using the keywords 'acute respiratory failure,' pneumonia prevention," 'risk stratification,' and 'preventive strategies.' Primary prevention focuses on reducing pneumonia risk through vaccination, smoking cessation, and comorbidity management. Secondary prevention involves early detection, risk assessment using clinical tools like the Pneumonia Severity Index (PSI) biomarkers, such as procalcitonin and C-reactive protein, appropriate antibiotic use, and emerging machine learning tools for real-time stratification. Tertiary prevention focuses on optimizing care with noninvasive respiratory support, lung-protective ventilation strategies, and ventilator bundles for intubated patients. Emerging therapies, including targeted use of corticosteroids and other immunomodulatory agents, are also discussed as promising adjuncts to current standards of care.

EXPERT OPINION

While these prevention strategies show potential, continued research is necessary to refine these interventions, explore newer therapies and evaluate long-term outcomes. Implementation of these strategies aims to reduce the impact of pneumonia-induced ARF on healthcare systems and improve patient survival and quality of care.

Comparative analysis of compartment-specific immunothrombotic biomarker profiles in bronchoalveolar lavage fluid and serum of patients with pneumonia-related acute respiratory distress syndrome: A preliminary cross-sectional study

Immunothrombosis has emerged as a potential mechanistic link underlying the development and progression of acute respiratory distress syndrome (ARDS), but understanding its specific profile in patients, both locally and systemically, is limited. The objective of this study was to characterize and compare the immunothrombotic signatures in patients diagnosed with pneumonia-related ARDS (p-ARDS) at both the pulmonary and systemic levels and to evaluate their clinical relevance. The study included 23 consecutive patients diagnosed with p-ARDS admitted to the intensive care unit at a tertiary university hospital from July 2022 to May 2023, alongside 40 concurrently hospitalized patients with common pneumonia as controls. Paired bronchoalveolar lavage fluid (BALF) and serum samples were collected from the participants for the analysis of 15 biomarkers to assess and quantify the pulmonary and systemic immunothrombotic signatures. The study results revealed significant pulmonary inflammation and systemic endothelial injury in p-ARDS patients compared to pneumonia controls. These observations were maintained after adjustment for severity of illness (Acute Physiology and Chronic Health Evaluation II scores). In terms of clinical relevance, inflammatory biomarkers (interleukin [IL]-6, IL-8) in BALF were found to correlate with PaO2/FiO2 ratio, while serum levels of a disintegrin and metalloproteinase with thrombospondin type 1 motif 13 (ADAMTS-13) and thrombomodulin showed associations with Sequential Organ Failure Assessment and Disseminated Intravascular Coagulation scores. In conclusion, this preliminary investigation identified compartment-specific variations in the immunothrombotic signature between patients with p-ARDS and those with pneumonia alone, with inflammatory responses predominantly localized in the alveolar compartments and coagulation/endothelial injury biomarkers more pronounced in peripheral blood.

Nanotherapy therapy for acute respiratory distress syndrome: a review

Acute respiratory distress syndrome (ARDS) is a complex and life-threatening disease characterized by severe respiratory failure. The lethality of ARDS remains alarmingly high, especially with the persistent ravages of coronavirus disease 2019 (COVID-19) in recent years. ARDS is one of the major complications of neocoronavirus pneumonia and the leading cause of death in infected patients. The large-scale outbreak of COVID-19 has greatly increased the incidence and mortality of ARDS. Despite advancements in our understanding of the causes and mechanisms of ARDS, the current clinical practice is still limited to the use of supportive medications to alleviate its progression. However, there remains a pressing need for effective therapeutic drugs to combat this devastating disease. In this comprehensive review, we discuss the commonly used therapeutic drugs for ARDS, including steroids, vitamin C, targeted inhibitors, and heparin. While these medications have shown some promise in managing ARDS, there is still a significant gap in the availability of definitive treatments. Moreover, we highlight the potential of nanocarrier delivery systems, such as liposomes, lipid nanoparticles, polymer nanoparticles, and inorganic nanoparticles, as promising therapeutic approaches for ARDS in the future. These innovative delivery systems have demonstrated encouraging results in early clinical trials and offer the potential for more targeted and effective treatment options. Despite the promising early results, further clinical trials are necessary to fully assess the efficacy and safety of nanotherapies for ARDS. Additionally, more in-depth research should be conducted to focus on the continuous development of precision therapies targeting different stages of ARDS development or different triggers. This will provide more ideas and rationale for the treatment of ARDS and ultimately lead to better patient outcomes.

Dexamethasone alleviates acute lung injury in a rat model with venovenous extracorporeal membrane oxygenation support

BACKGROUND

In recent years, dexamethasone (Dex) has been used to treat acute respiratory distress syndrome (ARDS) in patients with COVID-19 and achieved promising outcomes. Venovenous extracorporeal membrane oxygenation (VV ECMO) support for patients with ARDS has increased significantly worldwide. However, it remains unknown whether Dex could improve the efficiency of VV ECMO to reduce lung injury. Here, we investigate the combined efficiency of VV ECMO and Dex in rats with acute lung injury (ALI).

METHODS

We established VV ECMO in oleic acid (OA)-treated ALI rats and administered Dex. We conducted HE staining and evaluated lung and bronchoalveolar lavage (BAL) fluid cytokines to assess lung injury and inflammation. Furthermore, we investigated the activation of Hippo/YAP signalling in alveolar epithelial type II cell (AT2)-mediated alveolar epithelial repair using quantitative PCR, Western blotting and immunofluorescence. In vitro, the human alveolar epithelial cell line A549 was used to investigate the key role of YAP in alveolar epithelial cell differentiation.

RESULTS

VV ECMO combined with Dex alleviated OA-induced lung injury and pulmonary inflammation. Pulmonary oedema and exudation were significantly alleviated, and the lung and BAL levels of IL-6, IL-8 and TNF-α were significantly reduced compared with those observed with ECMO alone. In addition, VV ECMO combined with Dex treatment protected alveolar epithelial cells by activating Hippo/YAP signalling. In vitro, Dex promoted YAP expression and alveolar epithelial cell differentiation, whereas YAP knockdown inhibited YAP-mediated differentiation.

CONCLUSIONS

Our findings suggest that adjuvant Dex treatment during VV ECMO could alleviate ALI and pulmonary inflammation by activating the Hippo/YAP signalling pathway, which promoted alveolar regeneration and AT2 differentiation.

Senescence in Alveolar Epithelial Type II Cells Promotes Acute Lung Injury and Impairs Regeneration

The mortality associated with acute lung injury (ALI) increases with age. Alveolar epithelial type II (AEII) cells are the progenitor cells of the alveolar epithelium and are crucial for repair after injury. We hypothesize that telomere dysfunction-mediated AEII cell senescence impairs regeneration and promotes the development of ALI. To discriminate between the impact of old age and AEII cell senescence in ALI, young (3 mo) and old (18 mo) Sftpc-Ai9 mice with surfactant protein c mediated tdTomato expression, and young Sftpc-Ai9-Trf1 mice with additional telomeric repeat-binding factor 1 (Trf1) knockout-mediated senescence in AEII cells were treated with 1 μg LPS per gram body weight (n = 9-11). Control mice received saline solution (n = 7). Mice were killed 4 or 7 days later. Lung mechanics, pulmonary inflammation, and proteomes were analyzed, and parenchymal injury, AEII cell proliferation and AEI cell differentiation rate were quantified using stereology. Old mice showed 55% mortality by Day 4, whereas all young mice survived. Pulmonary inflammation was most severe in old Sftpc-Ai9 mice, followed by Sftpc-Ai9-Trf1 mice. Young Sftpc-Ai9 mice recovered almost completely by Day 7, whereas Sftpc-Ai9-Trf1 mice still showed mild signs of injury. An expansion of AEII cells was measured only in young Sftpc-Ai9 mice at Day 7. Aging and telomere dysfunction-mediated senescence had no impact on AEI differentiation rate in controls, but the reduced number of AEII cells in Sftpc-Ai9-Trf1 mice also affected de novo differentiation after injury. In conclusion, telomere dysfunction- mediated AEII cell senescence promoted parenchymal inflammation in ALI, but did not enhance mortality like old age. Although the differentiation rate remained functional with old age and AEII cell senescence, AEII cell proliferative capacity was impaired in ALI, affecting the regenerative ability.

The impact of a lung-protective ventilation mode using transpulmonary driving pressure titrated positive end-expiratory pressure on the prognosis of patients with acute respiratory distress syndrome

OBJECTIVE

This study aimed to assess the impact of a lung-protective ventilation strategy utilizing transpulmonary driving pressure titrated positive end-expiratory pressure (PEEP) on the prognosis [mechanical ventilation duration, hospital stay, 28-day mortality rate and incidence of ventilator-associated pneumonia (VAP), survival outcome] of patients with Acute Respiratory Distress Syndrome (ARDS).

METHODS

A total of 105 ARDS patients were randomly assigned to either the control group (n = 51) or the study group (n = 53). The control group received PEEP titration based on tidal volume [A tidal volume of 6 mL/kg, flow rate of 30-60 L/min, frequency of 16-20 breaths/min, constant flow rate, inspiratory-to-expiratory ratio of 1:1 to 1:1.5, and a plateau pressure ≤ 30-35 cmH2O. PEEP was adjusted to maintain oxygen saturation (SaO2) at or above 90%, taking into account blood pressure], while the study group received PEEP titration based on transpulmonary driving pressure (Esophageal pressure was measured as a surrogate for pleural pressure using an esophageal pressure measurement catheter connected to the ventilator. Tidal volume and PEEP were adjusted based on the observed end-inspiratory and end-expiratory transpulmonary pressures, aiming to maintain a transpulmonary driving pressure below 15 cmH2O during mechanical ventilation. Adjustments were made 2-4 times per day). Statistical analysis and comparison were conducted on lung function indicators [oxygenation index (OI), arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2)] as well as other measures such as heart rate, mean arterial pressure, and central venous pressure in two groups of patients after 48 h of mechanical ventilation. The 28-day mortality rate, duration of mechanical ventilation, length of hospital stay, and ventilator-associated pneumonia (VAP) incidence were compared between the two groups. A 60-day follow-up was performed to record the survival status of the patients.

RESULTS

In the control group, the mean age was (55.55 ± 10.51) years, with 33 females and 18 males. The pre-ICU hospital stay was (32.56 ± 9.89) hours. The mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was (19.08 ± 4.67), and the mean Murray Acute Lung Injury score was (4.31 ± 0.94). In the study group, the mean age was (57.33 ± 12.21) years, with 29 females and 25 males. The pre-ICU hospital stay was (33.42 ± 10.75) hours. The mean APACHE II score was (20.23 ± 5.00), and the mean Murray Acute Lung Injury score was (4.45 ± 0.88). They presented a homogeneous profile (all P > 0.05). Following intervention, significant improvements were observed in PaO2 and OI compared to pre-intervention values. The study group exhibited significantly higher PaO2 and OI compared to the control group, with statistically significant differences (all P < 0.05). After intervention, the study group exhibited a significant increase in PaCO2 (43.69 ± 6.71 mmHg) compared to pre-intervention levels (34.19 ± 5.39 mmHg). The study group's PaCO2 was higher than the control group (42.15 ± 7.25 mmHg), but the difference was not statistically significant (P > 0.05). There were no significant differences in hemodynamic indicators between the two groups post-intervention (all P > 0.05). The study group demonstrated significantly shorter mechanical ventilation duration and hospital stay, while 28-day mortality rate and incidence of ventilator-associated pneumonia (VAP) showed no significant differences. Kaplan-Meier survival analysis revealed a significantly better survival outcome in the study group at the 60-day follow-up (HR = 0.565, 95% CI: 0.320-0.999).

CONCLUSION

Lung-protective mechanical ventilation using transpulmonary driving pressure titrated PEEP effectively improves lung function, reduces mechanical ventilation duration and hospital stay, and enhances survival outcomes in patients with ARDS. However, further study is needed to facilitate the wider adoption of this approach.

Research progress of mitochondrial dysfunction induced pyroptosis in acute lung injury

Acute lung injury (ALI) is a common critical respiratory disease in clinical practice, especially in the ICU, with a high mortality rate. The pathogenesis of ALI is relatively complex, mainly involving inflammatory response imbalance, oxidative stress, cell apoptosis, and other aspects. However, currently, the treatment measures taken based on the above mechanisms have not had significant effects. Recent research shows that mitochondrial dysfunction and pyroptosis play an important role in ALI, but there is not much analysis on the relationship between mitochondrial dysfunction and pyroptosis at present. This article reviews the situation of mitochondrial dysfunction in ALI, pyroptosis in ALI, whether mitochondrial dysfunction is related to pyroptosis in ALI, and how to do so, and further analyzes the relationship between them in ALI. This review describes how to alleviate mitochondrial dysfunction, and then suppress the associated immunological pyroptosis, providing new ideas for the clinical treatment of ALI.

Role of miR-455-3p in the alleviation of LPS-induced acute lung injury by allicin

Acute lung injury (ALI) is a type of diffuse lung injury that seriously affects the survival of critically ill patients. MicroRNAs (miRNAs) can serve as promising therapeutic targets or offer insights for the development of potential therapeutic strategies against ALI. In our previous study, we demonstrated the protective effect of allicin in ALI, but the role of miRNAs in the alleviation of ALI by allicin remains unclear. This study aimed to investigate whether miRNAs mediate the effects of allicin on ALI. Cell viability and proliferation were determined using CCK-8 and EdU assays, respectively, while cellular apoptosis was analyzed by flow cytometry. The claudin-4 protein was detected by quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) and western blotting. The binding of miR-455 with claudin-4 was determined by bioinformatics analysis and validated by dual luciferase reporter assays. The lung wet/dry ratio of lipopolysaccharide (LPS)-treated rats was determined by hematoxylin and eosin (HE) and TUNEL staining of the pulmonary tissues. The levels of myeloperoxidase (MPO), interleukin (IL)-2, IL-6, and tumor necrosis factor (TNF)-α were determined by enzyme-linked immunosorbent assay (ELISA). We observed that allicin alleviated LPS-induced injury in A549 cells, and claudin-4 knockdown reversed the protective effect of allicin in ALI. Claudin-4 is a direct target of miR-455-3p, and miR-455-3p overexpression partially reversed the protective effect of allicin in LPS-treated A549 cells. Subsequent in vivo experiments confirmed that allicin protects against LPS-induced ALI by regulating the miR-455-3p/claudin-4 axis. The study revealed that the protective effect of allicin in ALI is mediated via miR-455-3p, which suppresses the expression of claudin-4.

Serum Free Fatty Acid Concentration Predicts ARDS after Off-Pump CABG: A Prospective Observational Study

BACKGROUND

Free fatty acids (FFAs) are established risk factors for various cardiovascular and metabolic disorders. Elevated FFAs can trigger inflammatory response, which may be associated with the occurrence of acute respiratory distress syndrome (ARDS) in cardiac surgery. In this prospective study, we aimed to investigate the association between circulating FFA and the incidence of ARDS, as well as the length of ICU stay, in patients undergoing off-pump coronary artery bypass grafting (CABG).

METHODS

We conducted a single-center, prospective, observational study among patients undergoing off-pump CABG. The primary endpoint was the occurrence of ARDS within 6 days after off-pump CABG. Serum FFA were measured at baseline and 24 h post-procedure, and the difference (Δ-FFA) was calculated.

RESULTS

A total of 180 patients were included in the primary analysis. The median FFA was 2.3 mmol/L (quartile 1 [Q1]-Q3, 1.4-3.2) at baseline and 1.5 mmol/L (Q1-Q3, 0.9-2.3) 24 h after CABG, with a Δ-FFA of 0.6 mmol/L (Q1-Q3, -0.1 to 1.6). Patients with elevated Δ-FFA levels had a significantly higher ARDS occurrence (55.6% vs. 22.2%; P < 0.001). Elevated Δ-FFA after off-pump CABG correlated with a significantly lower PaO2/FiO2 ratio, prolonged mechanical ventilation, and extended length of ICU stay. The area under the curve (AUC) of Δ-FFA for predicting ARDS (AUC, 0.758; 95% confidence interval, 0.686-0.831) significantly exceeded the AUC of postoperative FFA (AUC, 0.708; 95% CI 0.628-0.788; P < 0.001).

CONCLUSIONS

Elevated Δ-FFA levels correlated with ARDS following off-pump CABG. Monitoring FFA may assist in identifying high-risk patients for ARDS, facilitating timely interventions to improve clinical outcomes.

Platelet count as a prognostic marker for acute respiratory distress syndrome

BACKGROUND

This study aimed to evaluate the role of platelet count (PLT) in the prognosis of patients with acute respiratory distress syndrome (ARDS).

METHODS

The data were extracted from the Medical Information Mart for Intensive Care database (version 2.2). Patients diagnosed with ARDS according to criteria from Berlin Definition and had the platelet count (PLT) measured within the first day after intensive care unit admission were analyzed. Based on PLT, ARDS patients were divided into four groups: PLT ≤ 100 × 109/L, PLT 101-200 × 109/L, PLT 201-300 × 109/L, and PLT > 300 × 109/L. The primary outcome was 28-day mortality. Survival probabilities were analyzed using Kaplan-Meier. Furthermore, the association between PLT and mortality in ARDS patients was assessed using a univariate and multivariable Cox proportional hazards model.

RESULTS

Overall, the final analysis included 3,207 eligible participants with ARDS. According to the Kaplan-Meier curves for 28-day mortality of PLT, PLT ≤ 100 × 109/L was associated with a higher incidence of mortality (P = 0.001), the same trends were observed in the 60-day (P = 0.001) and 90-day mortality (P = 0.001). In the multivariate model adjusted for the potential factors, the adjusted hazard ratio at PLT 101-200 × 109/L group, PLT 201-300 × 109/L, and PLT > 300 × 109/L was 0.681 [95% confidence interval (CI): 0.576-0.805, P < 0.001], 0.733 (95% CI: 0.604-0.889, P = 0.002), and 0.787 (95% CI: 0.624-0.994, P = 0.044) compared to the reference group (PLT ≤ 100 × 109/L), respectively. Similar relationships between the PLT ≤ 100 × 109/L group and 28-day mortality were obtained in most subgroups.

CONCLUSION

PLT appeared to be an independent predictor of mortality in critically ill patients with ARDS.

sEH activity is associated with mortality in patients with ARDS: a retrospective cohort study

Aim: We hypothesized plasma sEH activity correlates with mortality in acute respiratory distress syndrome (ARDS) patients.Methods: Adult patients diagnosed with ARDS enrolled between 2017 and 2019 were included in this study.Results: A total of 337 adult patients met our inclusion criteria. Among them, 107 patients died within 28 days. The plasma sEH activity was higher in nonsurvivors relative to survivors. And a receiver operating characteristic curve with the area under the curve of 0.81 (95% confidence interval: 0.74-0.89) for the prediction of 28-day mortality was obtained. Its sensitivity and specificity were 72.5% and 74.6%, respectively.Conclusion: Elevated plasma sEH activity is associated with higher 28-day mortality in adult patients with ARDS.

Potential Impact of Subphenotyping in Pharmacologic Management of Acute Respiratory Distress Syndrome

Background: Acute respiratory distress syndrome (ARDS) is an acute inflammatory process in the lungs associated with high morbidity and mortality. Previous research has studied both nonpharmacologic and pharmacologic interventions aimed at targeting this inflammatory process and improving ventilation. Hypothesis: To date, only nonpharmacologic interventions including lung protective ventilation, prone positioning, and high positive end-expiratory pressure ventilation strategies have resulted in significant improvements in patient outcomes. Given the high mortality associated with ARDS despite these advancements, interest in subphenotyping has grown, aiming to improve diagnosis and develop personalized treatment approaches. Data Collection: Previous trials evaluating pharmacologic therapies in heterogeneous populations have primarily demonstrated no positive effect, but hope to show benefit when targeting specific subphenotypes, thus increasing their efficacy, while simultaneously decreasing adverse effects. Results: Although most studies evaluating pharmacologic therapies for ARDS have not demonstrated a mortality benefit, there is limited data evaluating pharmacologic therapies in ARDS subphenotypes, which have found promising results. Neuromuscular blocking agents, corticosteroids, and simvastatin have resulted in a mortality benefit when used in patients with the hyper-inflammatory ARDS subphenotype. Therapeutic Opinion: The use of subphenotyping could revolutionize the way ARDS therapies are applied and therefore improve outcomes while also limiting the adverse effects associated with their ineffective use. Future studies should evaluate ARDS subphenotypes and their response to pharmacologic intervention to advance this area of precision medicine.

Sivelestat improves acute lung injury by inhibiting PI3K/AKT/mTOR signaling pathway

OBJECTIVE

To investigate the therapeutic effect and mechanism of sivelestat sodium on acute lung injury (AIL).

METHODS

A rat model for ALI/acute respiratory distress syndrome (ALI/ARDS) was established. Pathological examination of lung tissue was conducted to assess lung injury. Blood gas in the arteries was measured using a blood analyzer. Changes in PaO2, PaO2/FiO2, and lung wet/dry (W/D) weight ratio were carefully compared. ELISA assay was conducted to estimate cell adhesion and inflammation response. Finally, real-time reverse transcription polymerase chain reaction and western blotting assay was used to determine the activation of PI3K/AKT/mTOR pathway.

RESULTS

ARDS in vivo model was successfully constructed by LPS injection. Compared with the sham group, PaO2 and PaO2/FiO2 were significantly lower in the vehicle group, while the lung W/D ratio, the lung injury score, NE, VCAM-1, IL-8 andTNF-αwere significantly increased. After treatment with different doses of sivelestat sodium, we found PaO2, PaO2/FiO2 were prominently increased, while the lung W/D ratio, the lung injury score, NE, VCAM-1, IL-8, TNF-α levels were decreased in the dose-dependent manner. Meanwhile, compared with the vehicle group, the expression levels of Bax, PI3K, Akt and mTOR were significantly lower, and the expression of Bcl-2 was significantly higher after injection with sivelestat sodium.

CONCLUSION

Sivelestat sodium has an interventional effect on ALI in sepsis by inhibiting the PI3K/AKT/mTOR signalling pathway.

Targeting BRD4 with PROTAC degrader ameliorates LPS-induced acute lung injury by inhibiting M1 alveolar macrophage polarization

OBJECTIVES

Acute lung injury (ALI) is a highly inflammatory condition with the involvement of M1 alveolar macrophages (AMs) polarization, eventually leading to the development of non-cardiogenic edema in alveolar and interstitial regions, accompanied by persistent hypoxemia. Given the significant mortality rate associated with ALI, it is imperative to investigate the underlying mechanisms of this condition so as to identify potential therapeutic targets. The therapeutic effects of the inhibition of bromodomain containing protein 4 (BRD4), an epigenetic reader, has been proven with high efficacy in ameliorating various inflammatory diseases through mediating immune cell activation. However, little is known about the therapeutic potential of BRD4 degradation in acute lung injury.

METHODS

This study aimed to assess the protective efficacy of ARV-825, a novel BRD4-targeted proteolysis targeting chimera (PROTAC), against ALI through histopathological examination in lung tissues and biochemical analysis in bronchoalveolar lavage fluid (BALF). Additionally, the underlying mechanism by which BRD4 regulated M1 AMs was elucidated by using CUT & Tag assay.

RESULTS

In this study, we found the upregulation of BRD4 in a lipopolysaccharide (LPS)-induced ALI model. Furthermore, we observed that intraperitoneal administration of ARV-825, significantly alleviated LPS-induced pulmonary pathological changes and inflammatory responses. These effects were accompanied by the suppression of M1 AMs. In addition, our findings revealed that the administration of ARV-825 effectively suppressed M1 AMs by inhibiting the expression of IRF7, a crucial transcriptional factor involved in M1 macrophages.

CONCLUSION

Our study suggested that targeting BRD4 using ARV-825 is a potential therapeutic approach for ALI.

Clinical outcomes of corticosteroid administration for acute respiratory distress syndrome in adults based on meta-analyses and trial sequential analysis

BACKGROUND

Acute respiratory distress syndrome (ARDS), which results in lung injury as a consequence of sepsis and septic shock, is associated with severe systemic inflammation and is responsible for a high worldwide mortality rate.

OBJECTIVE

Investigate whether corticosteroids could benefit clinical outcomes in adult with ARDS.

METHODS

A comprehensive search of electronic databases Ovid MEDLINE, Ovid EMbase, and Cochrane Library from their inception to 7 May 2023 was conducted to identify studies that met the eligibility criteria, including only randomized controlled trials. The study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the methods of trial sequential analysis.

MAIN OUTCOME MEASURES

Mortality rates, including including the 14-, 28-, 45-, and 60-day mortality, hospital mortality, and intensive care unit (ICU) mortality.

SAMPLE SIZE

17 studies with 2508 patients.

RESULTS

Data relating to mortality at 14, 28, 45, and 60 days were not significantly different when treatments with corticosteroids and placebo were compared. In terms of hospital and ICU mortality, the mortality of those who had received corticosteroids was significantly lower than that of those who had not. ARDS patients who received assisted ventilation benefited from corticosteroid therapy, as revealed by the significant difference in outcome days between those who received assisted ventilation and those who did not. Corticosteroid had significantly more days free from mechanical ventilation, ICU-free days, and MODS-free days during the first 28 days, but not more organ support-free days up to day 28.

CONCLUSION

Although corticosteroid therapy did not reduce mortality rates at different observation periods, it significantly reduced hospital and ICU mortality. Administering corticosteroids to ARDS patients significantly decreased the days of assisted ventilation and time cost consumption. This study confirmed that long-term use of low-dose glucocorticoids may have a positive effect on early ARDS.

LIMITATION

Risk of bias due to the differences in patient characteristics.

21st century critical care medicine: An overview

Critical care medicine in the 21st century has witnessed remarkable advancements that have significantly improved patient outcomes in intensive care units (ICUs). This abstract provides a concise summary of the latest developments in critical care, highlighting key areas of innovation. Recent advancements in critical care include Precision Medicine: Tailoring treatments based on individual patient characteristics, genomics, and biomarkers to enhance the effectiveness of therapies. The objective is to describe the recent advancements in Critical Care Medicine. Telemedicine: The integration of telehealth technologies for remote patient monitoring and consultation, facilitating timely interventions. Artificial intelligence (AI): AI-driven tools for early disease detection, predictive analytics, and treatment optimization, enhancing clinical decision-making. Organ Support: Advanced life support systems, such as Extracorporeal Membrane Oxygenation and Continuous Renal Replacement Therapy provide better organ support. Infection Control: Innovative infection control measures to combat emerging pathogens and reduce healthcare-associated infections. Ventilation Strategies: Precision ventilation modes and lung-protective strategies to minimize ventilator-induced lung injury. Sepsis Management: Early recognition and aggressive management of sepsis with tailored interventions. Patient-Centered Care: A shift towards patient-centered care focusing on psychological and emotional well-being in addition to medical needs. We conducted a thorough literature search on PubMed, EMBASE, and Scopus using our tailored strategy, incorporating keywords such as critical care, telemedicine, and sepsis management. A total of 125 articles meeting our criteria were included for qualitative synthesis. To ensure reliability, we focused only on articles published in the English language within the last two decades, excluding animal studies, in vitro/molecular studies, and non-original data like editorials, letters, protocols, and conference abstracts. These advancements reflect a dynamic landscape in critical care medicine, where technology, research, and patient-centered approaches converge to improve the quality of care and save lives in ICUs. The future of critical care promises even more innovative solutions to meet the evolving challenges of modern medicine.

Post-operative sepsis-induced acute respiratory distress syndrome: risk factors for a life-threatening complication

Introduction

Prevalence and mortality of the acute respiratory distress syndrome (ARDS) in intensive care units (ICU) are unacceptably high. There is scarce literature on post-operative sepsis-induced ARDS despite that sepsis and major surgery are conditions associated with ARDS. We aimed to examine the impact of post-operative sepsis-induced ARDS on 60-day mortality.

Methods

We performed a secondary analysis of a prospective observational study in 454 patients who underwent major surgery admitted into a single ICU. Patients were stratified in two groups depending on whether they met criteria for ARDS. Primary outcome was 60-day mortality of post-operative sepsis-induced ARDS. Secondary outcome measures were potential risk factors for post-operative sepsis-induced ARDS, and for 60-day mortality.

Results

Higher SOFA score (OR 1.1, 95% CI 1.0-1.3, p = 0.020) and higher lactate (OR 1.9, 95% CI 1.2-2.7, p = 0.004) at study inclusion were independently associated with ARDS. ARDS patients (n = 45) had higher ICU stay [14 (18) vs. 5 (11) days, p < 0.001] and longer need for mechanical ventilation [6 (14) vs. 1 (5) days, p < 0.001] than non-ARDS patients (n = 409). Sixty-day mortality was higher in ARDS patients (OR 2.7, 95% CI 1.1-6.3, p = 0.024). Chronic renal failure (OR 4.0, 95% CI 1.2-13.7, p = 0.026), elevated lactate dehydrogenase (OR 1.7, 95% CI 1.1-2.7, p = 0.015) and higher APACHE II score (OR 2.7, 95% CI 1.3-5.4, p = 0.006) were independently associated with 60-day mortality.

Conclusion

Post-operative sepsis-induced ARDS is associated with higher 60-day mortality compared to non-ARDS post-operative septic patients. Post-operative septic patients with higher severity of illness have a greater risk of ARDS and worse outcomes. Further investigation is needed in post-operative sepsis-induced ARDS to prevent ARDS.

Predictive performance of the variation rate of the driving pressure on the outcome of invasive mechanical ventilation in patients with acute respiratory distress syndrome

PURPOSE

To assess the value of the driving pressure variation rate (ΔP%) in predicting the outcome of weaning from invasive mechanical ventilation in patients with acute respiratory distress syndrome.

METHODS

In this case-control study, a total of 35 patients with moderate-severe acute respiratory distress syndrome were admitted to the intensive care unit between January 2022 and December 2022 and received invasive mechanical ventilation for at least 48 h were enrolled. Patients were divided into successful weaning group and failed weaning group depending on whether they could be removed from ventilator support within 14 days. Outcome measures including driving pressure, PaO2:FiO2, and positive end-expiratory pressure, etc. were assessed every 24 h from day 0 to day 14 until successful weaning was achieved. The measurement data of non-normal distribution were presented as median (Q1, Q3), and the differences between groups were compared by Wilcoxon rank sum test. And categorical data use the Chi-square test or Fisher's exact test to compare. The predictive value of ΔP% in predicting the outcome of weaning from the ventilator was analyzed using receiver operating characteristic curves.

RESULTS

Of the total 35 patients included in the study, 17 were successful vs. 18 failed in weaning from a ventilator after 14 days of mechanical ventilation. The cut-off values of the median ΔP% measured by Operator 1 vs. Operator 2 in the first 4 days were ≥ 4.17% and 4.55%, respectively (p < 0.001), with the area under curve of 0.804 (sensitivity of 88.2%, specificity of 64.7%) and 0.770 (sensitivity of 88.2%, specificity of 64.7%), respectively. There was a significant difference in mechanical ventilation duration between the successful weaning group and the failure weaning group (8 (6, 13) vs. 12 (7.5, 17.3), p = 0.043). The incidence of ventilator-associated pneumonia in the successful weaning group was significantly lower than in the failed weaning group (0.2‰ vs. 2.3‰, p = 0.001). There was a significant difference noted between these 2 groups in the 28-day mortality (11.8% vs. 66.7%, p = 0.003).

CONCLUSION

The median ΔP% in the first 4 days of mechanical ventilation showed good predictive performance in predicting the outcome of weaning from mechanical ventilation within 14 days. Further study is needed to confirm this finding.

Bletilla striata polysaccharides protect against ARDS by modulating the NLRP3/caspase1/GSDMD and HMGB1/TLR4 signaling pathways to improve pulmonary alveolar macrophage pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Bletilla striata polysaccharides (BSP) extracted from the B. striata tuber, have been demonstrated to possess anti-inflammatory properties. However, their potential protective effect against ARDS and their role in regulating cell pyroptosis remained unexplored.

AIM OF THE STUDY

The aim of this study was to investigate the therapeutic effect of BSP in the alleviation of lipopolysaccharide (LPS)-induced ARDS, and to explore its mechanism of action.

METHODS

The effect of BSP was assessed by LPS injection into the intraperitoneal cavity in vivo; pathological changes of ARDS mice were gauged by immunohistochemical, hematoxylin and eosin staining, and immunofluorescence assays. MH-S cells were used to model the pyroptosis in vitro. Finally, the pyroptosis of alveolar macrophage was detected by western blots, qPCR, and flow cytometry for NLRP3/caspase1/GSDMD and HMGB1/TLR4 pathway-associated proteins and mRNA.

RESULTS

BSP could significantly increase the weight and survival rate of mice with ARDS, alleviate the cytokine storm in the lungs, and reduce lung damage in vivo. BSP inhibited the inflammation caused by LPS/Nigericin significantly in vitro. Compared with the control group, there was a remarkable surge in the incidence of pyroptosis observed in ARDS lung tissue and alveolar macrophages, whereas BSP significantly diminished the pyroptosis ratio. Besides, BSP reduced NLRP3/caspase1/GSDMD and HMGB1/TLR4 levels in ARDS lung tissue and MH-S cells.

CONCLUSIONS

These findings proved that BSP could improve LPS-induced ARDS via inhibiting pyroptosis, and this effect was mediated by NLRP3/caspase1/GSDMD and HMGB1/TLR4, suggesting a therapeutic potential of BSP as an anti-inflammatory agent for ARDS treatment.

Predictive value of combination of lung injury prediction score and receptor for advanced glycation end‑products for the occurrence of acute respiratory distress syndrome

The present study evaluated the predictive value of the combination of the lung injury prediction score (LIPS) and receptor for advanced glycation end-products (RAGE) for the occurrence of acute respiratory distress syndrome (ARDS) in critically ill patients with ARDS risk factors. A total of 551 patients with risk factors of ARDS were divided into an ARDS group and a non-ARDS group. LIPS was computed within 6 h of admission into the ICU, and the plasma concentration of RAGE was detected within 24 h of admission. Multivariate analysis was performed to identify independent associations, and the predictive values for ARDS occurrence were assessed with receiver operating characteristic (ROC) curve. Within 7 days after admission into the ICU, ARDS occurred in 176 patients (31.9%). Multivariate analysis demonstrated that LIPS [odds ratio (OR), 1.282; 95% confidence interval (CI), 1.108-1.604], RAGE levels (OR, 2.359; 95% CI, 1.351-4.813) and Acute Physiology and Chronic Health Evaluation II score (OR, 1.167; 95% CI, 1.074-1.485) were independently associated with ARDS occurrence. ROC curves demonstrated that the area under curve (AUC) of LIPS, RAGE levels and their combination was 0.714 [standard error (SE), 0.023; 95% CI, 0.670-0.759], 0.709 (SE, 0.025; 95% CI, 0.660-0.758) and 0.889 (SE, 0.014; 95% CI, 0.861-0.917), respectively. The AUC of LIPS combined with RAGE levels was significantly higher compared with those of LIPS (0.889 vs. 0.714; Z=6.499; P<0.001) and RAGE (0.889 vs. 0.709; Z=6.282; P<0.001) levels alone. In conclusion, both LIPS and RAGE levels were independently associated with ARDS occurrence in critically ill patients with ARDS risk factors, and had medium predictive values for ARDS occurrence. Combination of LIPS with RAGE levels increased the predictive value for ARDS occurrence.

Nicotine plays a protective role in rats with induced viral pneumonia with polyinosinic-polycytidylic acid through α7nAChR

Objective

To study the effect of nicotine in rat model of pneumonia induced by polyinosinic-polycytidylic acid [Poly (I:C)] and explore the underlying mechanism.

Methods

Twenty-four healthy adult male Sprague-Dawley (SD) rats (200-250 g) were randomly divided into normal saline control group (NS group); Poly (I:C) group; nicotine group (NIC group); and α7 nicotinic acetylcholine receptor (α7nAChR) antagonist group (α-BGT group) (n = 6 each). Rats in the Poly (I: C), NIC, and α-BGT groups were administered 1.5 mg/mL 100 μL Poly (I:C) intranasally to establish pneumonia model. In α-BGT group, 1 μg/kg α-bungarotoxin (α-BGT) was intraperitoneally injected 45 min before intranasal Poly (I:C), and 400 μg/kg nicotine was intraperitoneally injected 15 min after α-BGT injection. The NIC group received an equal volume of NS in place of α-BGT while the other treatments were same. The Poly (I:C) group received equal volume of NS in place of nicotine while the other treatments were same as in NIC group. In the NS group, only NS was administered at all three time points. PaCO2, PaO2, and PaO2/FiO2 levels were determined 24 h after administration of Poly (I:C). After euthanization, rat lung tissues were extracted for pathological examination, and wet weight/dry weight (W/D ratio) was determined. Expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β, and interferon (IFN)-γ in lung tissue was determined by ELISA. q-PCR was used to detect nuclear factor kappa-B P65 (NF-κBP65).

Results

Compared with NS group, Poly (I:C) and α-BGT groups showed significantly increased W/D ratio, PaCO2, TNF-α, IL-6, IL-1β, and IFN-γ content, NF-κB P65 expression, and reduced PaO2 and PaO2/FiO2 (p < 0.05), along with obvious signs of pathological injury. Nicotine pre-treatment reduced W/D ratio, PaCO2, proinflammatory cytokines, NF-κBP65 expression, and increased PaO2 and PaO2/FiO2 levels. The above effects were negated in α-BGT group.

Conclusion

Pre-administration of nicotine improved Poly (I:C)-induced pneumonia by activating the cholinergic anti-inflammatory pathway.

Treatment with sivelestat sodium of acute respiratory distress syndrome induced by chemical pneumonitis: A report of three cases

Inhalation of acid fumes and aspiration of liquid substances or gastric contents may not initiate dyspnea within several hours after exposure but may result in delayed onset of alveolar edema. The present report presents three cases of inhalation or aspiration of chemical substances that resulted in acute respiratory distress syndrome (ARDS). Due to different underlying reasons, three patients developed ARDS resulting from chemical pneumonitis and pulmonary infection. From patients with dyspnea, dry rales could be heard in both lungs, with <92% percutaneous oxygen saturation at room air. All patients were treated using a high-flow nasal cannula and sivelestat sodium. Oxygenation gradually improved and the patients were discharged without adverse events. These cases suggest that early treatment with sivelestat sodium may improve the clinical outcomes of patients with ARDS.

Who needs clinician attention first? A qualitative study of critical care clinicians' needs that enable the prioritization of care for populations of acutely ill patients

BACKGROUND

To adequately care for groups of acutely ill patients, clinicians maintain situational awareness to identify the most acute needs within the entire intensive care unit (ICU) population through constant reappraisal of patient data from electronic medical record and other information sources. Our objective was to understand the information and process requirements of clinicians caring for multiple ICU patients and how this information is used to support their prioritization of care among populations of acutely ill patients. Additionally, we wanted to gather insights on the organization of an Acute care multi-patient viewer (AMP) dashboard.

METHODS

We conducted and audio-recorded semi-structured interviews of ICU clinicians who had worked with the AMP in three quaternary care hospitals. The transcripts were analyzed with open, axial, and selective coding. Data was managed using NVivo 12 software.

RESULTS

We interviewed 20 clinicians and identified 5 main themes following data analysis: (1) strategies used to enable patient prioritization, (2) strategies used for optimizing task organization, (3) information and factors helpful for situational awareness within the ICU, (4) unrecognized or missed critical events and information, and (5) suggestions for AMP organization and content. Prioritization of critical care was largely determined by severity of illness and trajectory of patient clinical status. Important sources of information were communication with colleagues from the previous shift, bedside nurses, and patients, data from the electronic medical record and AMP, and physical presence and availability in the ICU.

CONCLUSIONS

This qualitative study explored ICU clinicians' information and process requirements to enable the prioritization of care among populations of acutely ill patients. Timely recognition of patients who need priority attention and intervention provides opportunities for improvement of critical care and for preventing catastrophic events in the ICU.

Rab26 promotes macrophage phagocytosis through regulation of MFN2 trafficking to mitochondria

Acute respiratory distress syndrome (ARDS) is an inflammatory disorder of the lungs caused by bacterial or viral infection. Timely phagocytosis and clearance of pathogens by macrophages are important in controlling inflammation and alleviating ARDS. However, the precise mechanism of macrophage phagocytosis remains to be explored. Here, we show that the expression of Rab26 is increased in Escherichia coli- or Pseudomonas aeruginosa-stimulated bone marrow-derived macrophages. Knocking out Rab26 reduced phagocytosis and bacterial clearance by macrophages. Rab26 interacts with mitochondrial fusion protein mitofusin-2 (MFN2) and affects mitochondrial reactive oxygen species generation by regulating MFN2 transport. The levels of MFN2 in mitochondria were reduced in Rab26-deficient bone marrow-derived macrophages, and the levels of mitochondrial reactive oxygen species and ATP were significantly decreased. Knocking down MFN2 using small interfering RNA resulted in decreased phagocytosis and killing ability of macrophages. Rab26 knockout reduced phagocytosis and bacterial clearance by macrophages in vivo, significantly increased inflammatory factors, aggravated lung tissue damage, and increased mortality in mice. Our results demonstrate that Rab26 regulates phagocytosis and clearance of bacteria by mediating the transport of MFN2 to mitochondria in macrophages, thus alleviating ARDS in mice and potentially in humans.

SCNN1B regulates the proliferation, migration, and collagen deposition of human lung fibroblasts

The aim of this study was to investigate the role of amiloride-sensitive sodium channel protein 1B (SCNN1B) on the proliferation and migration of human lung fibroblasts and the possible mechanism that promote the development of acute respiratory distress syndrome (ARDS). Cultivate human embryonic lung fibroblasts (MRC-5) in vitro and screen out the most effective small interfering RNA to silence the expression of SCNN1B. Then, quantitative real-time PCR (qRT-PCR), CCK-8, Transwell, and Western blot detections were performed separately. The results of qRT-PCR showed that all three SCNN1B siRNAs were able to significantly decrease the mRNA expression level of SCNN1B compared with the si-NC group (P < 0.01), with the most significant decrease in the SCNN1B siRNA-83 group. Additionally, compared with the si-NC group, the proliferation ability of MRC-5 cells in the si-SCNN1B group was significantly enhanced, and the migration rate was significantly decreased (P < 0.01). Western blot results showed that low expression of SCNN1B significantly inhibited the protein expression levels of collagen deposition related proteins Collagen I and Heat shock proteins 47 (P < 0.01). In summary, SCNN1B can inhibit cell proliferation and promote cell migration and extracellular matrix deposition of human lung fibroblasts, and may be involved in the occurrence and development of ARDS.

Ventilator-associated events: From surveillance to optimizing management

Mechanical ventilation (MV) is a life-support therapy that may predispose to morbid and lethal complications, with ventilator-associated pneumonia (VAP) being the most prevalent. In 2013, the Center for Disease Control (CDC) defined criteria for ventilator-associated events (VAE). Ten years later, a growing number of studies assessing or validating its clinical applicability and the potential benefits of its inclusion have been published. Surveillance with VAE criteria is retrospective and the focus is often on a subset of patients with higher than lower severity. To date, it is estimated that around 30% of ventilated patients in the intensive care unit (ICU) develop VAE. While surveillance enhances the detection of infectious and non-infectious MV-related complications that are severe enough to impact the patient's outcomes, there are still many gaps in its classification and management. In this review, we provide an update by discussing VAE etiologies, epidemiology, and classification. Preventive strategies on optimizing ventilation, sedative and neuromuscular blockade therapy, and restrictive fluid management are warranted. An ideal VAE bundle is likely to minimize the period of intubation. We believe that it is time to progress from just surveillance to clinical care. Therefore, with this review, we have aimed to provide a roadmap for future research on the subject.

Orally administered BZL-sRNA-20 oligonucleotide targeting TLR4 effectively ameliorates acute lung injury in mice

The global COVID-19 pandemic emerged at the end of December 2019. Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are common lethal outcomes of bacterial lipopolysaccharide (LPS), avian influenza virus, and SARS-CoV-2. Toll-like receptor 4 (TLR4) is a key target in the pathological pathway of ARDS and ALI. Previous studies have reported that herbal small RNAs (sRNAs) are a functional medical component. BZL-sRNA-20 (Accession number: B59471456; Family ID: F2201.Q001979.B11) is a potent inhibitor of Toll-like receptor 4 (TLR4) and pro-inflammatory cytokines. Furthermore, BZL-sRNA-20 reduces intracellular levels of cytokines induced by lipoteichoic acid (LTA) and polyinosinic-polycytidylic acid (poly (I:C)). We found that BZL-sRNA-20 rescued the viability of cells infected with avian influenza H5N1, SARS-CoV-2, and several of its variants of concern (VOCs). Acute lung injury induced by LPS and SARS-CoV-2 in mice was significantly ameliorated by the oral medical decoctosome mimic (bencaosome; sphinganine (d22:0)+BZL-sRNA-20). Our findings suggest that BZL-sRNA-20 could be a pan-anti-ARDS ALI drug.

Paritaprevir ameliorates experimental acute lung injury in vitro and in vivo

Paritaprevir is a potent inhibitor of the NS3/4A protease used to treat chronic hepatitis C virus infection. However, its therapeutic effect on acute lung injury (ALI) remains to be elucidated. In this study, we investigated the effect of paritaprevir on a lipopolysaccharide (LPS)-induced two-hit rat ALI model. The anti-ALI mechanism of paritaprevir was also studied in human pulmonary microvascular endothelial (HM) cells following LPS-induced injury in vitro. Administration of 30 mg/kg paritaprevir for 3 days protected rats from LPS-induced ALI, as reflected by the changes in the lung coefficient (from 0.75 to 0.64) and lung pathology scores (from 5.17 to 5.20). Furthermore, the levels of the protective adhesion protein VE-cadherin and tight junction protein claudin-5 increased, and the cytoplasmic p-FOX-O1 and nuclear β-catenin and FOX-O1 levels decreased. Similar effects were observed in vitro with LPS-treated HM cells, including decreased nuclear β-catenin and FOX-O1 levels and higher VE-cadherin and claudin-5 levels. Moreover, β-catenin inhibition resulted in higher p-FOX-O1 levels in the cytoplasm. These results suggested that paritaprevir could alleviate experimental ALI via the β-catenin/p-Akt/ FOX-O1 signaling pathway.

Ferroptosis-related signature and immune infiltration characterization in acute lung injury/acute respiratory distress syndrome

BACKGROUND

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is one of the most life-threatening diseases in the intensive care unit with high mortality and morbidity. Ferroptosis is a newly discovered immune related cell death that is associated with various lung diseases. However, the role of immune-mediated ferroptosis in ALI/ARDS has not been elucidated.

METHOD

We analyzed two Gene Expression Omnibus (GEO) datasets (GSE2411 and GSE109913) and extracted characteristic ferroptosis-related genes (FRGs) between the control and ALI groups through bioinformatic analysis. Then, we prospectively collected bronchoalveolar lavage fluid (BALF) from patients with ARDS and verified the expression of characteristic FRGs. Lastly, we constructed the ALI/ARDS model induced by LPS and isolated the primary neutrophils of mice. Erastin, an ferroptosis inducer, was used at the cellular level to verify the effect of neutrophils on ferroptosis in lung epithelium cells.

RESULT

We identified three characteristic FRGs, Cp, Slc39a14 and Slc7a11, by analyzing two gene expression profiling datasets. Immune infiltration analysis showed that the three characteristic genes were significantly positively correlated with the infiltration levels of neutrophils. We collected BALF from 59 ARDS patients to verify the expression of Cp, Slc7a11 and Slc39a14 in humans. The results showed that Cp was elevated in patients with severe ARDS (p = 0.019), Slc7a11 was significantly elevated in patients with moderate ARDS (p = 0.021) relative to patients with mild ARDS. The levels of neutrophils in the peripheral blood of ARDS patients were positively correlated with the expression levels of Slc7a11 (Pearson's R² = 0.086, p = 0.033). Three characteristic FRGs were significantly activated after the onset of ferroptosis (6 h) early in LPS induced ALI model, and that ferroptosis was alleviated after the organism compensated within 12 to 48 h. We extracted primary activated neutrophils from mice and co-cultured them with MLE-12 in transwell, Slc7a11, Cp and Slc39a14 in MLE-12 cells were significantly upregulated as the number of neutrophils increased. The results showed that neutrophil infiltration alleviated erastin-induced MDA accumulation, GSH depletion, and divalent iron accumulation, accompanied by upregulation of Slc7a11 and Gpx4, implying the existence of a compensatory effect of lipid oxidation in neutrophils after acute lung injury in the organism.

CONCLUSION

We identified three immune-mediated ferroptosis genes, namely, Cp, Slc7a11 and Slc39a14, which possibly regulated by neutrophils during the development of ALI, and their pathways may be involved in anti-oxidative stress and anti-lipid metabolism. Thus, the present study contributes to the understanding of ALI/ARDS and provide novel targets for future immunotherapeutic.

COVID-19 progression towards ARDS: a genome wide study reveals host factors underlying critical COVID-19

Coronavirus disease 2019 (COVID-19) is a viral infection produced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus epidemic, which was declared a global pandemic in March 2020. The World Health Organization has recorded around 43.3 billion cases and 59.4 million casualties to date, posing a severe threat to global health. Severe COVID-19 indicates viral pneumonia caused by the SARS-CoV-2 infections, which can induce fatal consequences, including acute respiratory distress syndrome (ARDS). The purpose of this research is to better understand the COVID-19 and ARDS pathways, as well as to find targeted single nucleotide polymorphism. To accomplish this, we retrieved over 100 patients' samples from the Sequence Read Archive, National Center for Biotechnology Information. These sequences were processed through the Galaxy server next generation sequencing pipeline for variant analysis and then visualized in the Integrative Genomics Viewer, and performed statistical analysis using t-tests and Bonferroni correction, where six major genes were identified as DNAH7, CLUAP1, PPA2, PAPSS1, TLR4, and IFITM3. Furthermore, a complete understanding of the genomes of COVID-19-related ARDS will aid in the early identification and treatment of target proteins. Finally, the discovery of novel therapeutics based on discovered proteins can assist to slow the progression of ARDS and lower fatality rates.

Rhein-attenuates LPS-induced acute lung injury via targeting NFATc1/Trem2 axis

BACKGROUND

Evidence indicated that the early stage transition of macrophages' polarization stages yielded a superior prognosis for acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Rhein (cassic acid) is one major component of many traditional Chinese medicines, and has been reported to perform with strong anti-inflammation capabilities. However, the role rhein played and the mechanism via which it did so in LPS-induced ALI/ARDS remain unclear.

METHODS

ALI/ARDS was induced by LPS (3 mg/kg, i.n, st), accompanied by the applications of rhein (50 and 100 mg/kg, i.p, qd), and a vehicle or NFATc1 inhibitor (10 mg/kg, i.p, qd) in vivo. Mice were sacrificed 48 h after modeling. Lung injury parameters, epithelial cell apoptosis, macrophage polarization, and oxidative stress were examined. In vitro, conditioned medium from alveolar epithelial cells stimulated by LPS was used for culturing a RAW264.7 cell line, along with rhein administrations (5 and 25 μM). RNA sequencing, molecule docking, biotin pull-down, ChIP-qPCR, and dual luciferase assay were performed to clarify the mechanisms of rhein in this pathological process.

RESULTS

Rhein significantly attenuated tissue inflammation and promoted macrophage M2 polarization transition in LPS-induced ALI/ARDS. In vitro, rhein alleviated the intracellular ROS level, the activation of P65, and thus the M1 polarization of macrophages. In terms of mechanism, rhein played its protective roles via targeting the NFATc1/Trem2 axis, whose function was significantly mitigated in both Trem2 and NFATc1 blocking experiments.

CONCLUSION

Rhein promoted macrophage M2 polarization transition by targeting the NFATc1/Trem2 axis to regulate inflammation response and prognosis after ALI/ARDS, which shed more light on possibilities for the clinical treatments of this pathological process.

Evaluation of Digital Health Strategy to Support Clinician-Led Critically Ill Patient Population Management: A Randomized Crossover Study

To investigate whether a novel acute care multipatient viewer (AMP), created with an understanding of clinician information and process requirements, could reduce time to clinical decision-making among clinicians caring for populations of acutely ill patients compared with a widely used commercial electronic medical record (EMR).

DESIGN

Single center randomized crossover study.

SETTING

Quaternary care academic hospital.

SUBJECTS

Attending and in-training critical care physicians, and advanced practice providers.

INTERVENTIONS

AMP.

MEASUREMENTS AND MAIN RESULTS

We compared ICU clinician performance in structured clinical task completion using two electronic environments-the standard commercial EMR (Epic) versus the novel AMP in addition to Epic. Twenty subjects (10 pairs of clinicians) participated in the study. During the study session, each participant completed the tasks on two ICUs (7-10 beds each) and eight individual patients. The adjusted time for assessment of the entire ICU and the adjusted total time to task completion were significantly lower using AMP versus standard commercial EMR (-6.11; 95% CI, -7.91 to -4.30 min and -5.38; 95% CI, -7.56 to -3.20 min, respectively; p < 0.001). The adjusted time for assessment of individual patients was similar using both the EMR and AMP (0.73; 95% CI, -0.09 to 1.54 min; p = 0.078). AMP was associated with a significantly lower adjusted task load (National Aeronautics and Space Administration-Task Load Index) among clinicians performing the task versus the standard EMR (22.6; 95% CI, -32.7 to -12.4 points; p < 0.001). There was no statistically significant difference in adjusted total errors when comparing the two environments (0.68; 95% CI, 0.36-1.30; p = 0.078).

CONCLUSIONS

When compared with the standard EMR, AMP significantly reduced time to assessment of an entire ICU, total time to clinical task completion, and clinician task load. Additional research is needed to assess the clinicians' performance while using AMP in the live ICU setting.

Development and Validation of an Acute Respiratory Distress Syndrome Prediction Model in Coronavirus Disease 2019: Updated Lung Injury Prediction Score

OBJECTIVE

To develop and validate an updated lung injury prediction score for coronavirus disease 2019 (COVID-19) (c-LIPS) tailored for predicting acute respiratory distress syndrome (ARDS) in COVID-19.

PATIENTS AND METHODS

This was a registry-based cohort study using the Viral Infection and Respiratory Illness Universal Study. Hospitalized adult patients between January 2020 and January 2022 were screened. Patients who qualified for ARDS within the first day of admission were excluded. Development cohort consisted of patients enrolled from participating Mayo Clinic sites. The validation analyses were performed on remaining patients enrolled from more than 120 hospitals in 15 countries. The original lung injury prediction score (LIPS) was calculated and enhanced using reported COVID-19-specific laboratory risk factors, constituting c-LIPS. The main outcome was ARDS development and secondary outcomes included hospital mortality, invasive mechanical ventilation, and progression in WHO ordinal scale.

RESULTS

The derivation cohort consisted of 3710 patients, of whom 1041 (28.1%) developed ARDS. The c-LIPS discriminated COVID-19 patients who developed ARDS with an area under the curve (AUC) of 0.79 compared with original LIPS (AUC, 0.74; P<.001) with good calibration accuracy (Hosmer-Lemeshow P=.50). Despite different characteristics of the two cohorts, the c-LIPS's performance was comparable in the validation cohort of 5426 patients (15.9% ARDS), with an AUC of 0.74; and its discriminatory performance was significantly higher than the LIPS (AUC, 0.68; P<.001). The c-LIPS's performance in predicting the requirement for invasive mechanical ventilation in derivation and validation cohorts had an AUC of 0.74 and 0.72, respectively.

CONCLUSION

In this large patient sample c-LIPS was successfully tailored to predict ARDS in COVID-19 patients.

Association between BUN/creatinine ratio and the risk of in-hospital mortality in patients with trauma-related acute respiratory distress syndrome: a single-centre retrospective cohort from the MIMIC database

OBJECTIVE

Recent studies have shown that blood urea nitrogen to creatinine (BUN/Cr) ratio might be an effective marker for the prognosis of patients with respiratory diseases. Herein, we aimed to assess the association between BUN/Cr ratio and the risk of in-hospital mortality in patients with trauma-related acute respiratory distress syndrome (ARDS).

DESIGN

A retrospective cohort study.

SETTING AND PARTICIPANTS

1034 patients were extracted from the Medical Information Mart for Intensive Care-III (MIMIC-III) database.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome of the study was in-hospital mortality, defined by the vital status at the time of hospital discharge (ie, survivors and non-survivors).

RESULTS

Of the total patients, 191 (18.5%) died in hospital. The median follow-up duration was 16.0 (8.3-26.6) days. The results showed that high level of BUN/Cr ratio was significantly associated with an increased risk of in-hospital mortality (15.54-21.43: HR=2.00, 95% CI: (1.18 to 3.38); >21.43: HR=1.76, 95% CI: (1.04 to 2.99)) of patients with trauma-related ARDS. In patients with trauma-related ARDS that aged ≥65 years old, male and female, Onychomycosis Severity Index (OSI)>98, Revised Trauma Score (RTS)>11, Simplified Acute Physiology Score II (SAPS-II)>37 and sequential organ failure assessment (SOFA) scores≤7, BUN/Cr ratio was also related to the increased risk of in-hospital mortality (all p<0.05). The predictive performance of BUN/Cr ratio for in-hospital mortality was superior to BUN or Cr, respectively, with the area under the curve of receiver operator characteristic curve at 0.6, and that association was observed in age, gender, OSI, RTS, SAPS-II and SOFA score subgroups.

CONCLUSION

BUN/Cr ratio may be a potential biomarker for the risk of in-hospital mortality of trauma-related ARDS, which may help the clinicians to identify high-risk individuals and to implement clinical interventions.

Fexofenadine protects against lipopolysaccharide-induced acute lung injury by targeting cytosolic phospholipase A2

OBJECTIVE

Acute lung injury (ALI) causes acute respiratory distress syndrome, with a high mortality rate of 40%, with currently available pharmacological treatments. Cytosolic phospholipase A2 (cPLA2) plays a critical role in the lipopolysaccharide (LPS)-induced pathology of ALI. This study assessed the therapeutic effects of fexofenadine (FFD), an on-market small-molecule drug that can target cPLA2 in LPS-induced ALI.

METHODS

Primary macrophages obtained from the bone marrow of wild-type and cPLA2 knockout mice and the alveolar macrophage cell line, MHS were used to test the inhibitory effect of FFD on the cPLA2/ERK/p65 signaling pathway, NF-κB p65 translocation, and cytokine and chemokine production. An LPS-induced ALI mouse model was used to assess the treatment effects of FFD. Flow cytometry detected subsets of macrophages and neutrophils. cPLA2 activity and downstream hydrolysates were detected. Treatment with a cPLA2 inhibitor or NF-κB p65 inhibitor confirmed that FFD functioned through the cPLA2/ERK/p65 signaling pathway by targeting cPLA2.

RESULTS

FFD reduced the infiltration of macrophages and neutrophils, decreased the protein secretion in bronchoalveolar lavage fluid, and reduced the production of TNFα, IL-1β, IL-6, MCP-1, and IL-8 in the lung, bronchoalveolar lavage fluid, and sera of LPS-induced ALI mice. FFD inhibited cPLA2 activity, suppressed the cPLA2/ERK/p65 signaling pathway, inhibited translocation of p65, and decreased the production of cytokines, chemokines, and downstream hydrolysates of cPLA2, arachidonic acid, and leukotriene B4.

CONCLUSION

FFD inhibits the cPLA2/ERK/p65 signaling pathway by targeting cPLA2. Therefore, FFD is promising as a therapeutic against cPLA2-involved diseases, particularly ALI.

Inhibition of gp130 alleviates LPS-induced lung injury by attenuating apoptosis and inflammation through JAK1/STAT3 signaling pathway

BACKGROUND AND OBJECTIVE

Acute lung injury or acute respiratory distress syndrome (ALI/ARDS) is a life-threatening respiratory disease. Gp130 is a signal transduction receptor that participates in a variety of essential biological processes. The biological function of gp130 in ALI/ARDS is unclear. This study aims to investigate the roles and potential mechanisms of gp130 in lung injury induced by lipopolysaccharide (LPS).

METHODS

The ALI/ARDS mouse model was established using intratracheal LPS administration. Hematoxylin and eosin staining and bronchoalveolar lavage fluid analysis were used to evaluate the degree of lung injury. Cell apoptosis was assessed by TUNEL staining, flow cytometry, and western blot. Then the expression of gp130, IL-6, IL-10, TNF-α, and the JAK1/STAT3 signaling pathway-related proteins was assessed by RT-PCR, western blot, and immunohistochemistry.

RESULTS

The expression of gp130 increased after 24 h of LPS treatment. Inhibiting gp130 improved inflammatory infiltration and alveolar collapsed, decreased IL-6 and TNF-α levels, raised IL-10 levels, and decreased cell apoptosis in LPS-induced mice. Meanwhile, suppressing gp130 reduced the inflammatory response and cell apoptosis in LPS-induced Beas-2B cells. Furthermore, p-JAK1 and p-STAT3 expressions were elevated after LPS stimulation and decreased following gp130 inhibition, suggesting that gp130 may regulate the JAK1/STAT3 signaling pathway in LPS-induced mice and Beas-2B cells.

CONCLUSION

The findings suggest that gp130 regulates the inflammatory response and cell apoptosis through the JAK1/STAT3 signaling pathway, thereby mitigating LPS-induced lung injury. Gp130 may be a potential therapeutic target for ALI/ARDS.

JAK-STAT signaling as an ARDS therapeutic target: Status and future trends

Acute respiratory distress syndrome (ARDS) is characterized by noncardiogenic pulmonary edema. It has a high mortality rate and lacks effective pharmacotherapy. With the outbreak of COVID-19 worldwide, the mortality of ARDS has increased correspondingly, which makes it urgent to find effective targets and strategies for the treatment of ARDS. Recent clinical trials of Janus kinase (JAK) inhibitors in treating COVID-19-induced ARDS have shown a positive outcome, which makes the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway a potential therapeutic target for treating ARDS. Here, we review the complex cause of ARDS, the molecular JAK/STAT pathway involved in ARDS pathology, and the progress that has been made in strategies targeting JAK/STAT to treat ARDS. Specifically, JAK/STAT signaling directly participates in the progression of ARDS or colludes with other pathways to aggravate ARDS. We summarize JAK and STAT inhibitors with ARDS treatment benefits, including inhibitors in clinical trials and preclinical studies and natural products, and discuss the side effects of the current JAK inhibitors to reveal future trends in the design of JAK inhibitors, which will help to develop effective treatment strategies for ARDS in the future.

The safety and efficacy of mesenchymal stromal cells in ARDS: a meta-analysis of randomized controlled trials

Mesenchymal stromal cells (MSC) have shown potential efficacy in both animal and human trials of acute respiratory distress syndrome (ARDS). Especially during the COVID-19 pandemic, MSC was intensely studied for treating COVID-19-induced ARDS. The purpose of this study is to evaluate the safety and efficacy of MSC in ARDS via a meta-analysis of randomized controlled trials (RCTs). Therefore, a meta-analysis of RCTs of MSC as a therapy for ARDS was conducted. The protocol of this review was registered on Open Science Framework. With no language restriction and according to the "PICOs" principle, searches were conducted on Pubmed and Embase to retrieve any clinical literature on MSC for ARDS. Any RCT, which compared MSC to controls for ARDS, where MSC and controls were intravenously infused, of any dosage, was eligible for inclusion. A total of 13 RCTs, which evaluated MSC versus control for treating ARDS, enrolling a total of 655 cases, met the inclusion criteria and appeared in this meta-analysis. A heterogeneity assessment was carried out using the χ² test, where a P value less than 0.05 was considered significant. The choice of a fixed-effect or a random-effect model was decided by the I² value in each of the analyses. This meta-analysis indicated that there was no significant difference in terms of adverse events between MSC and control for ARDS (OR = 0.64, 95% CI [0.34, 1.20], P = 0.17, and I² = 0%). In comparison with control, MSC could reduce the mortality of ARDS (OR = 0.66, 95% CI [0.46, 0.96], P = 0.03, and I² = 10%). Based on the results of our meta-analysis, the safety of MSC was demonstrated to be non-inferior to that of standard treatment, and MSC may reduce the mortality rate of ARDS. Though the heterogeneity in the main results was low (I² < 25%), more high-quality and large-scale clinical trials are needed to further confirm our findings.

Association of the C-terminal 42-peptide fragment of alpha-1 antitrypsin with the severity of ARDS: A pilot study

BACKGROUND

Acute respiratory distress syndrome is a life-threatening condition with a hospital mortality rate of up to 40%. Biomarkers related to the pathophysiology of ARDS may not only identify patients at risk but may also serve as potential therapeutic targets. This study examined the association between the proteolytic C-terminal 42-peptide fragment of alpha-1 antitrypsin and ARDS severity.

METHODS

The 42-peptide fragment and interleukin-6 levels were measured in 21 patients with mild-to-moderate ARDS and 47 patients with moderate-to-severe ARDS on days 1, 3, and 5 after diagnosis/admission to the intensive care unit. To elucidate the association between both biomarkers and the PaO₂/FiO₂ ratio, the concentrations of both biomarkers were compared between the two groups, and a multivariate regression analysis was performed.

RESULTS

The concentrations of both biomarkers were higher in patients with moderate-to-severe ARDS. While the PaO₂/FiO₂ ratio increased from day 1 to day 3, the concentrations of both biomarkers decreased. Multivariate regression analysis revealed negative associations between the PaO₂/FiO₂ ratio and both the C-terminal 42-peptide of alpha-1 antitrypsin and interleukin-6 on day 1 (beta: -0.138, p = 0.052; beta: -0.096, p = 0.004) and on day 3 (beta: -0.157, p = 0.045; beta: -0.106, p = 0.043).

INTERPRETATION

The C-terminal 42-peptide of alpha-1 antitrypsin is a new biomarker associated with ARDS severity. Its predictive value in identifying patients at risk of developing moderate-to-severe ARDS must be investigated in additional, independent prospective studies.

Pretreatment with rosavin attenuates PM2.5-induced lung injury in rats through antiferroptosis via PI3K/Akt/Nrf2 signaling pathway

Inflammation and oxidative stress caused by fine particulate matter (PM2.5) increase the incidence and mortality rates of respiratory disorders. Rosavin is the main chemical component of Rhodiola plants, which exerts anti-oxidative and antiinflammatory effects. In this research, the potential therapeutic effect of rosavin was investigated by the PM2.5-induced lung injury rat model. Rats were instilled with PM2.5 (7.5 mg/kg) suspension intratracheally, while rosavin (50 mg/kg, 100 mg/kg) was delivered by intraperitoneal injection before the PM2.5 injection. It was observed that rosavin could prevent lung injury caused by PM2.5. PM2.5 showed obvious ferroptosis-related ultrastructural alterations, which were significantly corrected by rosavin. The pretreatment with rosavin downregulated the levels of tissue iron, malondialdehyde, and 4-hydroxynonenal, and increased the levels of glutathione. The expression of nuclear factor E2-related factor 2 (Nrf2) was upregulated by rosavin, together with other ferroptosis-related proteins. RSL3, a specific ferroptosis agonist, reversed the beneficial impact of rosavin. The network pharmacology approach predicted the activation of rosavin on the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. LY294002, a potent PI3K inhibitor, decreased the upregulation of Nrf2 induced by rosavin. In conclusion, rosavin prevented lung injury induced by PM2.5 stimulation and suppressed ferroptosis via upregulating PI3K/Akt/Nrf2 signaling pathway.

Dexmedetomidine alleviates acute lung injury by promoting Tregs differentiation via activation of AMPK/SIRT1 pathway

OBJECTIVES

To explore the anti-inflammatory effect and the potential mechanism of dexmedetomidine in ARDS/ALI.

MATERIALS AND METHODS

C57BL/6 mice and EL-4 cells were used in this research. The ALI model was established by CLP. The level of inflammatory cytokines in the lung and blood, the severity of lung injury, the expression of Foxp3, and the proportion of Tregs were detected before and after dexmedetomidine treatment. The expression of the AMPK/SIRT1 after dexmedetomidine treatment was detected in vivo and in vitro. After blocking the AMPK/SIRT1 pathway or depleting Tregs in vivo, the level of the inflammatory response, tissue injury, and Tregs differentiation were detected again to clarify the effect of dexmedetomidine.

RESULTS

Dexmedetomidine significantly reduced systemic inflammation and lung injury in CLP mice. Dexmedetomidine enhanced the Foxp3 expression in the lungs and the frequency of Tregs in the spleen. Dexmedetomidine up-regulated the protein expression of p-AMPK and SIRT1 in lungs and EL-4 cells and facilitated the differentiation of naïve CD4⁺ T cells into Tregs in vitro. Meanwhile, DEX also increased the expression of Helios in Treg cells.

CONCLUSIONS

DEX could improve ARDS/ALI by facilitating the differentiation of Tregs from naïve CD4⁺ T cells via activating the AMPK/SIRT1 pathway.

Short-term prone positioning for severe acute respiratory distress syndrome after cardiopulmonary bypass: A case report and literature review

BACKGROUND

Aortic dissection is a complex and dangerous cardiovascular disease, with many complications in the perioperative period, including severe acute respiratory distress syndrome (ARDS), which affects prognosis and increases mortality. Despite the effect of prone positioning (PP) in improving oxygenation in patients with severe ARDS, reports about PP early after cardiac surgery are few and such an option may be an issue in cardiac surgery patients because of the recent sternotomy.

CASE SUMMARY

A 40-year-old male patient diagnosed with acute type A aortic dissection on October 22, 2021 underwent ascending artery replacement plus total aortic arch replacement plus stent elephant trunk implantation under cardiopulmonary bypass. Unfortunately, he developed ARDS on postoperative day 1. Despite comprehensive treatment with aggressive pulmonary protective ventilation, fluid management with continuous renal replacement therapy, the condition continued to deteriorate and rapidly progressed to severe ARDS with a minimum oxygenation index of 51. We are ready to implement salvage therapy, including PP and extracorporeal membrane oxygenation (ECMO). Due to the large amount of pericardial mediastinal and thoracic drainage after thoracotomy, ECMO may result in massive postoperative bleeding. Prolonged prone ventilation is often inappropriate after thoracotomy. Therefore, we chose short-term PP for < 6 h. Finally, the oxygenation index greatly improved and the diffuse exudation in both lungs of the patient was significantly reduced with short-term prone positioning.

CONCLUSION

Intermittent short-term PP can improve early postoperative severe ARDS after acute aortic dissection.

Diagnostic value of transpulmonary thermodilution measurements for acute respiratory distress syndrome in a pig model of septic shock

BACKGROUND

No direct approach assessing pulmonary vascular permeability exists in the current therapeutic strategy for patients with acute respiratory distress syndrome (ARDS). Transpulmonary thermodilution measures hemodynamic parameters such as pulmonary vascular permeability index and extravascular lung water, enabling clinicians to assess ARDS severity. The aim of this study is to explore a precise transpulmonary thermodilution-based criteria for quantifying the severity of lung injury using a clinically relevant septic-ARDS pig model.

METHODS

Thirteen female pigs (weight: 31 ± 2 kg) were intubated, mechanically ventilated under anesthesia, and either assigned to septic shock-induced ARDS or control group. To confirm the development of ARDS, we performed computed tomography (CT) imaging in randomly selected animals. The pulmonary vascular permeability index, extravascular lung water, and other hemodynamic parameters were consecutively measured during the development of septic lung injury. Lung status was categorized as normal (partial pressure of oxygen/fraction of inspired oxygen ≥ 400), or injured at different degrees: pre-ARDS (300-400), mild-to-moderate ARDS (100-300), or severe ARDS (< 100). We also measured serum inflammatory cytokines and high mobility group box 1 levels during the experiment to explore the relationship of the pulmonary vascular permeability index with these inflammatory markers.

RESULTS

Using CT image, we verified that animals subjected to ARDS presented an extent of consolidation in bilateral gravitationally dependent gradient that expands over time, with diffuse ground-glass opacification. Further, the post-mortem histopathological analysis for lung tissue identified the key features of diffuse alveolar damage in all animals subjected to ARDS. Both pulmonary vascular permeability index and extravascular lung water increased significantly, according to disease severity. Receiver operating characteristic analysis demonstrated that a cut-off value of 3.9 for the permeability index provided optimal sensitivity and specificity for predicting severe ARDS (area under the curve: 0.99, 95% confidence interval, 0.98-1.00; sensitivity = 100%, and specificity = 92.5%). The pulmonary vascular permeability index was superior in its diagnostic value than extravascular lung water. Furthermore, the pulmonary vascular permeability index was significantly associated with multiple parameters reflecting clinicopathological changes in animals with ARDS.

CONCLUSION

The pulmonary vascular permeability index is an effective indicator to measure septic ARDS severity.